Screenshare bugs

[datryn-ribdun]

• users report shared screen being cut into horizontal thirds ("The top and bottom are cut and you can't see the other person's screen")
• when users stop sharing screen, the video player doesn't close. Causes problems when start sharing -> stop sharing -> start sharing again.

Notes

I'm tracking these in one place, but they may be addressed in seprate PRs. If anyone finds other screenshare bugs, please comment so I can add them to this list